A field-sequential single LCD projector and a projection method

Abstract

The present invention provides a novel field-sequential single-LCD projector, which includes an LED light source, a light collection and collimation device, a light combining and color filtering device, an intermediate reflector, a focusing device, a light homogenization device, an exit lens group, an LCD light valve and a field lens, an imaging reflector and a projection lens, which are sequentially arranged in the light traveling direction. The LED light source includes a red light source, a green light source and a blue light source. Compared with the existing full-color light valve technology, under the same technical conditions, the efficiency of the light valve of the present invention is greatly improved, the power of the light source is greatly reduced, and the image color gamut is greatly improved, so that the projector can output higher brightness and has a broader market adaptability. At the same time, compared with the practical LCD light valve technology of pure field-sequential, the present invention can significantly reduce the bandwidth requirement for the driving IC and the response time of the liquid crystal, significantly reducing the engineering difficulty and R & D investment of productization and significantly reducing the raw material cost of the product.

Description

Technical Field

[0001] The present invention relates to the technical field of projectors, and particularly to a field-sequential single-LCD projector and a projection method. Background Art

[0002] The pure field-sequential single-LCD projector has many advantages such as simple structure, low energy consumption, high output brightness, and wide color gamut. In theory, it can rival the efficiency and effect of 3LCD and DLP projectors. For decades, people have been trying hard, but so far, no substantial results have been achieved, that is, products have not been successfully manufactured and put on the market to generate value.

[0003] The main reasons are as follows: First, the bandwidth requirement for the driving IC is too high, exceeding the manufacturing level in the past and at the present stage or the price-performance ratio expected by consumers. Second, the response speed requirement for the liquid crystal is too high, making it difficult to achieve productization ideally. Third, the technical side underestimated the picky degree of users for products. Serious deficiencies such as trailing, crosstalk, and ghosting are simply unacceptable to users, even though the brightness is indeed a bit higher and the power consumption is indeed much lower.

[0004] Actually, it is because the technology required for pure field-sequential (ideally, the R, G, and B fields are input in sequence without intervals) lags behind the market development. For example, the resolution of the mainstream single-LCD projector in 2004 was 320*240, while now it is already FHD. Now, it is not a problem to manufacture a pure field-sequential projector with a resolution of 320*240 (and ensure low cost and good quality), but now it is very difficult to manufacture a pure field-sequential projector with FHD resolution. Moreover, manufacturing a pure field-sequential projector with a resolution of 320*240 has no market demand anymore.

[0005] Therefore, it is necessary to find a feasible entry point between technology and the market to solve the above contradictions between technology and the market. This is the purpose of the field-sequential single-LCD projector of the present invention. The present invention can meet the market demand of the current FHD resolution and has the characteristics of high-efficiency light valve, low power consumption, wide image color gamut, high output brightness, etc. of the pure field-sequential single-LCD projector. It is mainly achieved by significantly reducing the bandwidth requirement for the driving IC, significantly reducing the response time of the liquid crystal, increasing the aperture ratio of the full-color LCD light valve, significantly reducing the engineering difficulty and R & D investment for productization, and significantly reducing the raw material cost of the product, etc. Summary of the Invention

[0006] The object of the present invention is to overcome the deficiencies of the prior art and provide a field-sequential single-LCD projector. The present invention has the characteristics of high-efficiency light valve, low power consumption, wide image color gamut, high output brightness, etc. of the pure field-sequential single-LCD projector.

[0007] To achieve the above object, the present invention provides a field sequential single LCD projector, which includes an LED light source, a light collection and collimation device, a light combining and color filtering device, an intermediate mirror, a focusing device, a light homogenizing device, an exit lens group, an LCD light valve, a field lens, an imaging mirror, and a projection lens, which are arranged in sequence along the direction of light travel.

[0008] The LED light source includes a red light source, a green light source, and a blue light source; the light collection and collimation device includes a red light collection and collimation module for collecting and collimating the light emitted by the red light source, a green light collection and collimation module for collecting and collimating the light emitted by the green light source, and a blue light collection and collimation module for collecting and collimating the light emitted by the blue light source; the red light collection and collimation module, the green light collection and collimation module, and the blue light collection and collimation module each include at least one lens.

[0009] The light combining and color filtering device combines and filters the light emitted by the red light collection and collimation module, the green light collection and collimation module, and the blue light collection and collimation module; the focusing device focuses the image of the LED light source on the incident end face of the light homogenizing device, thereby forming a real image of a secondary light source; the focusing device includes at least one lens; after the light homogenizing device uniformly processes the light of the real image of the secondary light source, the exit lens group uniformly illuminates the LCD light valve.

[0010] Further, the LCD light valve is a half-field sequential display light valve with a single primary color filter film, and any pixel of the LCD light valve includes two sub-pixels, namely a first sub-pixel and a second sub-pixel; correspondingly, each full-color image input to the LCD light valve is decomposed into sub-frame images of three primary colors, namely a red sub-frame, a green sub-frame, and a blue sub-frame.

[0011] The first sub-pixel is provided with a single primary color filter film and displays a sub-frame image of the same color as the filter film among the sub-frame images of the three primary colors.

[0012] The second sub-pixel has no filter film and alternately displays the other two sub-frame images among the sub-frame images of the three primary colors in a field sequential manner.

[0013] Correspondingly, a light source in the LED light source corresponding to the color of the filter film of the first sub-pixel is selectively lit with a duty cycle.

[0014] Correspondingly, when the second sub-pixel displays one of the other two sub-frame images in a field sequential manner, a light source of a corresponding color in the LED light source is selectively lit with a duty cycle.

[0015] Correspondingly, when the second sub-pixel displays the other of the other two sub-frame images in a field-sequential manner, a light source of a corresponding color in the LED light source is selectively lit with a duty cycle.

[0016] Further, let the time taken to display each frame of full-color image be T, and T is divided into a first time period t1 - t0, a second time period t2 - t1, a third time period t3 - t2, and a fourth time period t4 - t3. Then T=(t1 - t0)+(t2 - t1)+(t3 - t2)+(t4 - t3)=t4 - t0; correspondingly, the first sub-pixel displays one sub-frame image in time T; the second sub-pixel alternately displays the other two sub-frame images in a field-sequential manner within time T, specifically: the first time period t1 - t0 is for inserting a black field for the second sub-pixel, the second time period t2 - t1 is for the second sub-pixel to display one of the other two sub-frame images, the third time period t3 - t2 is for inserting a black field for the second sub-pixel, and the fourth time period t4 - t3 is for the second sub-pixel to display the other of the other two sub-frame images.

[0017] Correspondingly, a light source in the LED light source corresponding to the color of the color filter film of the first sub-pixel is selected to be correspondingly lit within the first time period t1 - t0 and the third time period t3 - t2.

[0018] Correspondingly, when the second sub-pixel displays one of the sub-frame images of the other two primary colors in the second time period t2 - t1, a light source in the LED light source corresponding to the color of one sub-frame image is selected to be lit within the second time period t2 - t1 for a time ≤t2 - t1.

[0019] Correspondingly, when the second sub-pixel displays the other of the other two sub-frame images in the fourth time period t4 - t3, a light source in the LED light source corresponding to the color of the other sub-frame image is selected to be lit within the fourth time period t4 - t3 for a time ≤t4 - t3.

[0020] Further, the LCD light valve is a black-and-white type half-field-sequential display light valve, and any pixel of the LCD light valve includes two black-and-white sub-pixels, namely a first sub-pixel and a second sub-pixel; correspondingly, each frame of full-color image input to the LCD light valve is decomposed into sub-frame images of three primary colors: a red sub-frame, a green sub-frame, and a blue sub-frame; let the time taken to display each frame of the full-color image be T:

[0021] The first sub-pixel selectively displays one of the sub-frame images of the three primary colors within the T.

[0022] Correspondingly, within the period T, the second sub-pixel alternately displays the other two of the sub-frame images of the three primary colors in a field-sequential manner.

[0023] Correspondingly, one light source in the LED light source corresponding to the color of a sub-frame image displayed by the first sub-pixel is selectively turned on with a duty cycle.

[0024] Correspondingly, when the second sub-pixel displays one of the other two sub-frame images in a field-sequential manner, one light source in the LED light source corresponding to the color of a sub-frame image is selectively turned on with a duty cycle.

[0025] Correspondingly, when the second sub-pixel displays the other of the other two sub-frame images in a field-sequential manner, one light source in the LED light source corresponding to the color of the other sub-frame image is selectively turned on with a duty cycle.

[0026] Further, assume that T is divided into a first time period t1 - t0, a second time period t2 - t1, a third time period t3 - t2, and a fourth time period t4 - t3. Then T=(t1 - t0)+(t2 - t1)+(t3 - t2)+(t4 - t3)=t4 - t0.

[0027] Correspondingly, the first sub-pixel displays one of the sub-frame images of the three primary colors in the first time period t1 - t0 and the third time period t3 - t2, and inserts a black field in the second time period t2 - t1 and the fourth time period t4 - t3.

[0028] Correspondingly, within the period T, the second sub-pixel alternately displays the other two sub-frame images of the primary colors in a field-sequential manner, specifically: a black field is inserted for the second sub-pixel in the first time period t1 - t0, the second sub-pixel displays one of the other two sub-frame images of the primary colors in the second time period t2 - t1, a black field is inserted for the second sub-pixel in the third time period t3 - t2, and the second sub-pixel displays the other of the other two sub-frame images of the primary colors in the fourth time period t4 - t3.

[0029] Correspondingly, one light source in the LED light source corresponding to the color of a sub-frame image of a primary color displayed by the first sub-pixel is selected to be turned on corresponding to a time less than or equal to t1 - t0 within the first time period t1 - t0 and less than or equal to t3 - t2 within the third time period t3 - t2.

[0030] Correspondingly, when the second sub-pixel displays one of the other two sub-frame images of the primary colors in the second time period t2 - t1, one light source in the LED light source corresponding to the color of a sub-frame image is selected to be turned on within the second time period t2 - t1 corresponding to a time less than or equal to t2 - t1.

[0031] Correspondingly, when the second sub-pixel displays another one of the sub-frame images of the other two primary colors during the fourth time period t4 - t3, one light source corresponding to the color of the other sub-frame image in the LED light source is selected to be lit within the fourth time period t4 - t3 for a time ≤ t4 - t3.

[0032] Furthermore, the light combining and color filtering device includes a BG dichroic plate and a CR dichroic plate.

[0033] The light emitting surfaces of the green light source and the blue light source are neither parallel nor coplanar; the BG dichroic plate is located between the light emitting surfaces of the green light source and the blue light source and combines the light of the green light source and the blue light source.

[0034] The light emitting surfaces of the red light source and the green light source are parallel, coplanar, non - parallel or non - coplanar; the CR dichroic plate combines the light from the BG dichroic plate and the red light source.

[0035] Furthermore, the light emitted from the light combining and color filtering device has: the spectral distributions of the red, green, and blue light have no overlap with each other, and the light combining and color filtering device outputs pure three - primary - color light; the overlapping spectra are filtered and blocked by the light combining and color filtering device.

[0036] Furthermore, the light emitted from the light combining and color filtering device has: the wavelength range of the overlapping spectral distributions of the red, green, and blue light is ≤ 50 nm, and the area of the overlapping region is ≤ 5% of the area enclosed by the spectrum of the light emitted from the light combining and color filtering device; the spectra with overlapping wavelengths > 50 nm and the area of the overlapping region > 5% of the area enclosed by the spectrum of the light emitted from the light combining and color filtering device are filtered and blocked by the light combining and color filtering device.

[0037] Furthermore, the red light collection and collimation module includes an R collection lens and an R collimation lens arranged in sequence along the light traveling direction; the green light collection and collimation module includes a G collection lens and a G collimation lens arranged in sequence along the light traveling direction; the blue light collection and collimation module includes a B collection lens and a B collimation lens arranged in sequence along the light traveling direction.

[0038] Preferably, the light homogenizing device includes a square - conical condenser.

[0039] Preferably, the exit lens group includes at least one lens, and the lens is a plano - convex free - form surface lens. The plane of the free - form surface lens is the incident surface, and the exit surface of the free - form surface lens is a free - form surface.

[0040] The present invention also provides a projection method for the above - mentioned field - sequential single - LCD projector, including the following steps:

[0041] The red light source, green light source, and blue light source respectively emit light. The red light collection and collimation module collects and collimates the light emitted by the red light source. The green light collection and collimation module collects and collimates the light emitted by the green light source. The blue light collection and collimation module collects and collimates the light emitted by the blue light source.

[0042] The light combining and color filtering device combines and filters the light emitted by the red light collection and collimation module, the green light collection and collimation module, and the blue light collection and collimation module. After being reflected by the intermediate mirror and focused by the focusing device in sequence, the image of the LED light source is focused on the incident end face of the light homogenizing device, thereby forming a real image of the secondary light source. After the light of the real image of the secondary light source is homogenized by the light homogenizing device, the LCD light valve is uniformly illuminated by the outgoing lens group. After the light passes through the LCD light valve, it is projected out through the field lens, imaging mirror, and projection lens in sequence.

[0043] The first sub-pixel of the LCD light valve displays one of the sub-frame images of the three primary colors. Correspondingly, one of the light sources in the LED light source corresponding to the color of the sub-frame image displayed by the first sub-pixel is selectively lit at a duty cycle.

[0044] The second sub-pixel alternately displays the sub-frame images of the other two primary colors in a field-sequential manner. Correspondingly, the two light sources in the LED light source corresponding to the colors of the other two sub-frame images are synchronously and alternately lit at a duty cycle corresponding to the two sub-frame images alternately displayed by the second sub-pixel.

[0045] Further, the area ratio δ of the first sub-pixel and the second sub-pixel in any one pixel is:

[0046] δ = S 81 / S 82 ;

[0047] δ = f(Φ 81 , Φ 821 , Φ 822 );

[0048] Where: S 81 is the area of the first sub-pixel; S 82 is the area of the second sub-pixel; Φ 81 is the luminous flux provided by the first sub-pixel; Φ 821 is the luminous flux provided by the second sub-pixel when field-sequentially displaying one sub-frame image of the other two primary colors; Φ 822 is the luminous flux provided by the second sub-pixel when field-sequentially displaying the other sub-frame image of the other two primary colors.

[0049] Further, the 81 , 821 , 822 , the relationship between the time consumption T of each full-color image frame and the optoelectronic characteristics of the LED light source is as follows:

[0050] 81 = f{[β( R , G , B )], Δt a , Δt c};

[0051] 821 = f{[β( R , G , B )], Δt b};

[0052] 822 = f{[β( R , G , B )], Δt d};

[0053] Wherein: β represents the mathematical meaning of "one of them" or "the corresponding one among them", that is, only the optoelectronic characteristics of one light source corresponding to the display color of the first sub-pixel 81 among R , G , B are considered; R is the optoelectronic characteristic of the red light source; G is the optoelectronic characteristic of the green light source; B is the optoelectronic characteristic of the blue light source; Δt a is related to the first time period t1 - t0, that is, the proportion or duty cycle within the first time period t1 - t0; Δt b is related to the second time period t2 - t1, that is, the proportion or duty cycle within the second time period t2 - t1; Δt c is related to the third time period t3 - t2, that is, the proportion or duty cycle within the third time period t3 - t2; Δt d is related to the fourth time period t4 - t3, that is, the proportion or duty cycle within the fourth time period t4 - t3.

[0054] Advantages of the present invention:

[0055] ​​​Compared with the existing full-color light valves, under the same technical conditions, the efficiency of the light valve of the present invention is greatly improved, the power of the light source is greatly reduced, and the color gamut of the image is greatly enhanced, enabling the projector to output higher brightness and have a broader market adaptability. At the same time, compared with the pure field-sequential LCD light valve technology, the present invention can significantly reduce the bandwidth requirements for the driving IC and the response time of the liquid crystal, significantly reducing the engineering difficulty and R & D investment for productization, and significantly reducing the raw material cost of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention, and those of ordinary skill in the art can obtain other drawings based on these drawings without creative efforts.

[0057] Figure 1 Schematic diagram of an embodiment of the present invention;

[0058] Figure 2 is Figure 1 a three-dimensional display diagram of;

[0059] Figure 3 Schematic diagram of the pixel of the LCD light valve of the present invention;

[0060] Figure 4 Schematic diagram of the signal duty cycle of an embodiment of the present invention;

[0061] Figure 5 Schematic diagram of the color filter curve of the LCD light valve of an embodiment of the present invention;

[0062] Figure 6 Schematic diagram of the spectral splitting of the LED light source of the present invention;

[0063] Figure 7 Schematic diagram of the 45° angle spectral splitting of the BG dichroic plate of the present invention;

[0064] Figure 8 Schematic diagram of the 45° angle spectral splitting of the CR dichroic plate of the present invention;

[0065] Figure 9 Schematic diagram of the signal duty cycle of another embodiment of the present invention;

[0066] Figure 10 Schematic diagram of the LCD light valve of the existing full-color technology.

[0067] Description of the above-mentioned reference numerals:

[0068] 101. Red light source, 102. Green light source, 103. Blue light source, 211. R collection lens, 212. R collimating lens, 221. G collection lens, 222. G collimating lens, 231. B collection lens, 232. B collimating lens, 31. BG dichroic plate, 32. CR dichroic plate, 4. Intermediate mirror, 51. First lens, 52. Second lens, 6. Light homogenizing device, 7. Exit lens group, 8. LCD light valve, 81. First sub-pixel, 82. Second sub-pixel, 84. BM, 85. FPC cable, 801. Any pixel, 9. Field lens, 10. Imaging mirror, 11. Projection lens. Detailed implementation mode

[0069] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be described in detail below with reference to the accompanying drawings. The description of this part is only exemplary and explanatory, and should not have any restrictive effect on the protection scope of the present invention.

[0070] It should be noted that similar reference numerals and letters denote similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0071] It should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the present invention is usually placed during use. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. In addition, the terms "first", "second", "third", etc. are only used for distinguishing descriptions and cannot be understood as indicating or implying relative importance.

[0072] In addition, the terms "horizontal", "vertical", "hanging", etc. do not mean that the components are required to be absolutely horizontal or hanging, but can be slightly inclined. For example, "horizontal" only means that its direction is more horizontal relative to "vertical", and does not mean that the structure must be completely horizontal, but can be slightly inclined.

[0073] In the description of the present invention, it should also be noted that unless otherwise clearly specified and limited, the terms "set", "installed", "connected", "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, and can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0074] Example 1:

[0075] Since the field-sequential display single-LCD projector involves many disciplines and technical applications such as physics, chemistry, materials, color engineering, and driving circuits in depth, necessary background introductions will be made in this example first.

[0076] Since 2004 in China, people have been continuously working hard. Refer to Chinese Patent Publication Nos. CN1645250A, CN102063001A, and CN110687737A, etc. That is, similar to a single-chip DLP projector, it displays the red, green, and blue monochromatic field (sub-frame) images of a full-color frame (or image, the same hereinafter) in chronological order, and uses the human visual persistence effect to synthesize a color image in the human brain. Due to the lack of significant breakthroughs in the response speed of the past LCD light valves (often dozens of milliseconds or even sub-second levels), the scarcity of driving chip resources, and some deficiencies and misunderstandings in people's understanding of field-sequential, such display technologies are extremely difficult in research and development and engineering, resulting in their inability to be practical. In recent years, the LCD light valve technology has made great progress. In particular, the relatively low cost of high-bandwidth driving chips has rapidly promoted the practical progress of field-sequential technology projection products.

[0077] At the end of the last century, companies such as Philips and JVC (Victor Company of Japan) abroad had field-sequential single-LCD rear projection products on the market. However, even today, the production of their products is extremely difficult because it requires multiple prisms to rotate precisely and at high speed, so they stopped production after a short attempt. According to common knowledge, the research on field-sequential display first appeared in the color improvement of black-and-white cameras and CRT televisions in 1950. Until the popularization of solid-state light sources such as LEDs, the corresponding color switching of the illumination light source in field-sequential display technology was usually achieved mechanically (such as the color wheel of a DLP projector). This can hardly achieve miniaturization and simplicity, and completely violates the theoretical characteristics of simple production and low cost of field-sequential display. Early patent technologies for reference today, such as the prototype field-sequential technology of Japanese Patent No. 2519429, etc., laid a feasible foundation for the subsequent research and development of LCD field-sequential display.

[0078] The black frame insertion technology introduced in the present invention is one of the emergency methods for early LCD display technologies with many drawbacks to quickly achieve or approach the display effect of CRT (cathode ray tube). With the progress of LCD technology itself, the black frame insertion technology faded out with the elimination of CRT.

[0079] For example, the refresh rate of an LCD monitor is 60 Hz. By increasing the refresh rate to 120 Hz or decreasing it to 30 Hz, a black frame is inserted between full-color frames to significantly improve the adverse feelings of the human eye such as color illusion and trailing.

[0080] In practice, the black insertion technology can effectively improve many deficiencies of the current field-sequential display. However, its disadvantage is that it affects the output brightness (luminous flux). Therefore, people do not consider it an optimizable technology and it has been ignored for a long time. People are more inclined to organically combine technologies such as using OCB (Optical Compensated Bend) and the field-sequential principle to achieve high-quality field-sequential display. In recent years, great progress has been made in technologies and processes such as the driving electric field method, liquid crystal cell thickness, dielectric constant, viscosity, elasticity, better anisotropy, liquid crystal injection, and alignment. Due to the too high market expectation value, the advanced concept of field-sequential display has hardly been practical in the past long time.

[0081] For the improvement of the output brightness of projectors or the effective reduction of input energy (more energy-saving), even if it is only a trivial 1% improvement, it should be taken seriously in the industry and is worth actively implementing.

[0082] The field-sequential display method provided by the present invention can obviously significantly reduce the energy consumption of a full-color single LCD projector, and thus has practical significance in aspects such as heat dissipation, raw material cost, noise, contrast ratio, black level, and especially energy conservation. At the same time, compared with the practical black insertion of the idealized pure field-sequential technology, the bandwidth requirement of the driving IC (or circuit) and the response time of the liquid crystal of the present invention can be significantly reduced, reducing the engineering difficulty and R & D investment of productization and the raw material cost of the product.

[0083] See Figures 1-4 As shown, a field-sequential single LCD projector provided in this embodiment includes an LED light source, a light collection and collimation device, a light combining and color filtering device, an intermediate mirror 4, a focusing device, a light homogenizing device 6, an exit lens group 7, an LCD light valve 8, a field lens 9, an imaging mirror 10, and a projection lens 11, which are arranged in sequence along the light traveling direction.

[0084] The LED light source includes a red light source 101, a green light source 102, and a blue light source 103. In fact, for the projection light source, it is not limited to LEDs, and laser light sources are also possible. However, it is almost impossible to balance the cost performance of the product for the cost of lasers matching a single LCD projector at the present stage and for a long time in the future.

[0085] The light collection and collimation device includes a red light collection and collimation module for collecting and collimating the light emitted by the red light source 101, a green light collection and collimation module for collecting and collimating the light emitted by the green light source 102, and a blue light collection and collimation module for collecting and collimating the light emitted by the blue light source 103.

[0086] The red light collection and collimation module, the green light collection and collimation module, and the blue light collection and collimation module each include at least one lens. In this embodiment, preferably but not limited to, the red light collection and collimation module includes an R collection lens 211 and an R collimation lens 212 arranged in sequence along the light traveling direction; preferably but not limited to, the green light collection and collimation module includes a G collection lens 221 and a G collimation lens 222 arranged in sequence along the light traveling direction; preferably but not limited to, the blue light collection and collimation module includes a B collection lens 231 and a B collimation lens 232 arranged in sequence along the light traveling direction.

[0087] In this embodiment, preferably but not limited to, the optical indexes of the R collection lens 211, the G collection lens 221, and the B collection lens 231 are the same, and preferably but not limited to, they are concave-convex lenses with the concave surface as the incident surface; preferably but not limited to, the optical indexes of the R collimation lens 212, the G collimation lens 222, and the B collimation lens 232 are the same, and preferably but not limited to, they are biconvex lenses, where the incident surface is spherical and the exit surface is aspherical, and the material is preferably but not limited to E48R, which is conducive to mass production as much as possible and maintaining a high cost performance.

[0088] The focusing device focuses the image of the LED light source at or near the incident end face (or entrance) of the light homogenizing device 6, thereby forming a real image of the secondary light source. It should be noted that because the depth of field of the focusing device cannot be a plane, and the focusing device itself always generates aberrations and other distortions, combined with the actual manufacturing accuracy, it is impossible to focus absolutely and without distortion at the incident end face of the light homogenizing device 6. The number of lenses included in the focusing device is at least one. In this embodiment, preferably but not limited to, the focusing device includes a first lens 51 and a second lens 52 to complete the focusing imaging. In fact, the number of lenses used for focusing imaging depends on the positioning requirements of the projector for the optical system, such as cost and volume, etc.

[0089] After the light homogenizing device 6 uniformly processes the light of the real image of the secondary light source, the exit lens group 7 uniformly illuminates the LCD light valve 8. In this embodiment, the light homogenizing device 6 includes a square pyramid condenser, and the exit lens group 7 includes at least one lens; the lens is preferably but not limited to a plano-convex free-form surface lens, where the plane is the incident surface and the exit surface is a free-form surface.

[0090] See Figure 3As shown, the LCD light valve 8 is a half - field - sequential light valve with a single - primary - color color filter film. Any pixel 801 of the LCD light valve 8 includes two sub - pixels, namely a first sub - pixel 81 and a second sub - pixel 82. Correspondingly, each frame of the full - color image input to the LCD light valve 8 is decomposed into a red sub - frame, a green sub - frame, and a blue sub - frame, that is, sub - frame images of three primary colors.

[0091] The first sub - pixel 81 has a single - primary - color color filter (Color Filter, i.e., CF), and displays a sub - frame image of the same color as the color filter film in the input full - color image. In this embodiment, preferably but not limited to, the single - primary - color color filter film of the first sub - pixel 81 is green, and the display of the green sub - frame image is completed.

[0092] The second sub - pixel 82 has no color filter film and is for pure black - and - white display. It alternately displays the other (or "another") two sub - frame images in the input full - color image by means of field - sequential. Correspondingly, in this embodiment, preferably but not limited to, the second sub - pixel 82 alternately displays the red sub - frame and the blue sub - frame images by field - sequential.

[0093] Correspondingly, one light source in the LED light source corresponding to the color of the color filter film of the first sub - pixel 81 is selectively lit with a duty cycle. In this embodiment, preferably, the green light source 102 corresponding to the green color filter film is selectively lit with a duty cycle.

[0094] Correspondingly, when the second sub - pixel 82 displays one of the other two sub - frame images in a field - sequential manner, one light source of the corresponding color in the LED light source is selectively lit with a duty cycle; when the second sub - pixel 82 displays the other of the other two sub - frame images in a field - sequential manner, one light source of the corresponding color in the LED light source is selectively lit with a duty cycle. In this embodiment, when the second sub - pixel displays the red sub - frame image in a field - sequential manner, the red light source 101 is selectively and synchronously lit with a duty cycle; when the second sub - pixel 82 displays the blue sub - frame image in a field - sequential manner, the blue light source 103 is selectively and synchronously lit with a duty cycle.

[0095] See Figure 4As shown in the figure, assume that the time taken to display each frame of full-color image is T (the abscissa represents time t or T, and 0 represents t0). T is divided into the first time period t1 - t0 (here, "-" does not mean "from t1 to t0", but t1 minus t0 or from t0 to t1, the same hereinafter), the second time period t2 - t1, the third time period t3 - t2, and the fourth time period t4 - t3. T=(t1 - t0)+(t2 - t1)+(t3 - t2)+(t4 - t3)=t4 - t0, and t4 - t0 is the T for inputting one frame of full-color image. Correspondingly, the first sub-pixel 81 displays a sub-frame image in time T; the second sub-pixel 82 alternately displays another two sub-frame images in a field-sequential manner within time T, specifically: in the first time period t1 - t0, a black field is inserted for the second sub-pixel 82; in the second time period t2 - t1, the second sub-pixel 82 displays one of the other two sub-frame images; in the third time period t3 - t2, a black field is inserted for the second sub-pixel 82; in the fourth time period t4 - t3, the second sub-pixel 82 displays the other of the other two sub-frame images. See Figure 4 As shown in the figure, in this embodiment, the display time of the green sub-frame image on the first sub-pixel 81 is T (see the green sub-frame switch pulse curve GC), while the red (see the red sub-frame switch pulse curve RC) and blue (see the blue sub-frame switch pulse curve BC) sub-frame images are alternately displayed on the second sub-pixel 82 in a field-sequential manner, specifically: in the first time period t1 - t0, a black field is inserted for the second sub-pixel 82 (see the black field switch pulse curve BAC); in the second time t2 - t1, the second sub-pixel 82 displays the red sub-frame image (see the pulse curve RC); in the third time period t3 - t2, a black field is inserted for the second sub-pixel 82 (see the pulse curve BAC); in the fourth time period t4 - t3, the second sub-pixel 82 displays the blue sub-frame image (see the pulse curve BC).

[0096] Correspondingly, one light source in the LED light source corresponding to the color of the color filter film of the first sub-pixel 81 is selected to be turned on corresponding to the first time period t1 - t0 and the third time period t3 - t2. See Figure 4 As shown in the figure, in this embodiment, the green light source 102 is turned on corresponding to the first time period t1 - t0 and the third time period t3 - t2, and is not turned on during the remaining time of T. See the green light source switch pulse curve GL in the figure.

[0097] Correspondingly, when the second sub-pixel 82 displays one of the other two sub-frame images in the second time period t2 - t1, one light source in the LED light source corresponding to the color of one of the sub-frame images is selected to be turned on within the second time period t2 - t1 for a time ≤t2 - t1. See Figure 4As shown, in this embodiment, when the second sub-pixel 82 displays a red sub-frame image during the second time period t2 - t1, the red light source 101 is synchronously lit within the second time period t2 - t1, and the selected lighting time < the value of t2 - t1. Refer to the red light source switching pulse curve RL in the figure.

[0098] Correspondingly, when the second sub-pixel 82 displays another one of the other two sub-frame images during the fourth time period t4 - t3, one of the LED light sources corresponding to the color of the other sub-frame image is selected to be lit within the fourth time period t4 - t3 for a time ≤ t4 - t3. Refer to Figure 4 As shown, in this embodiment, when the second sub-pixel 82 displays a blue sub-frame image during the fourth time period t4 - t3, the blue light source 103 is synchronously lit within the fourth time period t4 - t3, and the selected lighting time < the value of t4 - t3. Refer to the blue light source switching pulse curve BL in the figure. This is because even if black insertion is performed on the second sub-pixel 82, due to the extremely short time during which the liquid crystal flips from high speed to holding, lighting the corresponding light source for irradiation is still disadvantageous and of little significance.

[0099] Furthermore, this embodiment achieves full-color display in a half-field sequential manner, that is, the first sub-pixel 81 of the LCD light valve 8 displays a sub-frame image, such as a green sub-frame image, within the T time. The first sub-pixel does not have a field sequential mode and is the same as the light valve of the existing full-color technology, belonging to a "constant brightness" display mode; while the second sub-pixel 82 displays the other two sub-frame images in a field sequential manner, such as a red sub-frame and a blue sub-frame image. The red sub-frame is displayed during the second time period t2 - t1, and the blue sub-frame is displayed during the fourth time period t4 - t3. Black field images are inserted during the first time period t1 - t0 and the third time period t3 - t2. Correspondingly, the green light source 102 is lit during the first time period t1 - t0 and the third time period t3 - t2 respectively. The red light source 101 is synchronously lit within the second time period t2 - t1, but the lighting time < the value of t2 - t1. Similarly, the blue light source 103 is synchronously lit within the fourth time period t4 - t3, but the lighting time < the value of t4 - t3.

[0100] Refer to Figure 4As shown, within time T, the first sub-pixel 81 constantly displays the green sub-frame image. At this time, as long as there is green light irradiation, a green sub-frame image can be output, which is projected through the field lens 9, imaging mirror 10, and projection lens 11. The green light source 102 is lit respectively in the first time period t1 - t0 and the third time period t3 - t2, and is extinguished at other times (see the pulse curve GL). Since the first sub-pixel 81 constantly displays the green sub-frame image, and green (nearby) is one of the most sensitive colors to the human eye, the most sensitive frame is constantly lit without field-sequential alternation, creating an objective condition for reducing the flicker of the image output by the field-sequential single LCD projector. At the same time, compared with the pure field-sequential single LCD projector, the green image light source in this embodiment is lit once in each of the first time period t1 - t0 and the third time period t3 - t2, also objectively reducing the image flicker caused by the light source alternation by twice.

[0101] When the green light source 102 is lit respectively in the first time period t1 - t0 and the third time period t3 - t2, at this time, the second sub-pixel 82 outputs a black field and is in a blocking state, so the green light will not leak out through the second sub-pixel 82, and the LCD light valve 8 only outputs a normal green sub-frame image.

[0102] Within the second time period t2 - t within time T, the second sub-pixel 82 displays the red sub-frame image, and correspondingly, the duty cycle of the red light source 101 is selectively lit synchronously. At this time, in addition to illuminating the second sub-pixel 82, the red light source 101 also illuminates the first sub-pixel 81. However, since the first sub-pixel 81 is equipped with a green color filter film, when the red light irradiates the first sub-pixel 81, the red light will be completely blocked by the green CF. At this time, the LCD light valve 8 only outputs a pure red sub-frame image. The principle of the second sub-pixel 82 displaying the blue sub-frame image within the fourth time period t4 - t3 is similar, and at this time, the LCD light valve 8 only outputs a pure blue sub-frame image. Thus, a field-sequential single LCD projector in this embodiment completes the display of full-color images.

[0103] Continue to refer to Figure 3 As shown, the influence of the BM (84 in the figure, i.e., Black Matrix, black matrix) on the transmittance of the LCD light valve 8 has become relatively obvious in the current era of FHD resolution. Taking the 3.5-inch FHD light valve of BOE as an example, the size of each pixel is about 40μm * 40μm (micrometers). If the line width ( Figure 3 “W” in it) of the BM is 4μm, then the pixel aperture is [1 - (40 * 4 * 2 + 32 * 4 * 2) / (40 * 40)] * 100% = 64%. Refer to Figure 10For the existing full-color technology light valve, any pixel 801' of the full-color LCD light valve 8' in the figure includes a red color filter film 81', a green color filter film 82' and a blue color filter film 83'. Between the color filter films is BM (84' in the figure). Under the condition of the same size, the pixel aperture ratio is [1 -

[0104] (40 * 4 * 2 + 32 * 4 * 3) / (40 * 40)] * 100% = 56%. Obviously, compared with the traditional full-color light valve technology, the pixel aperture ratio of this embodiment has increased by about 14.3%, and accordingly, the transmittance has been increased.

[0105] Continue to refer to Figure 10 As shown, while keeping the white balance basically normal, assume that the red light source irradiating the LCD light valve 8' is 1500 Lm (lumens), with a power of 33 W, the green light source is 5000 Lm, with a power of 53 W, and the blue light source is 500 Lm, with a power of 40 W. The total is 7000 Lm, and the power is 126 W. Assume that the efficiency of the lighting system is 80%, the polarization light efficiency is 40%, and losses such as field lenses and lenses are not considered. The CF (Color Filter) efficiency of the LCD light valve 8' is a relatively high 25%. Then the projector can output:

[0106] 7000 * 0.8 * 0.4 * 0.575 * 0.25 = 322 Lm.

[0107] Refer to Figure 3 As shown, in this embodiment, under the same conditions of maintaining white balance, assume that T is divided into four equal parts. The red light source 101 is 750 Lm (one-fourth of 3000 Lm), with a power of 16.5 W, the green light source 102 is 2500 Lm (one-half of 5000 Lm), with a power of 26.5 W, and the blue light source 103 is 250 Lm (one-fourth of 1000 Lm), with a power of 20 W. The total is 3500 Lm, and the power is 63 W. Then the projector can output:

[0108] (5000 * 0.25 * 2 + 3000 * 0.25 + 1000 * 0.25) * 0.8 * 0.4 * 0.65 * 0.5 = 364 Lm.

[0109] Obviously, the power consumption of this embodiment is only half of the existing technology, and the output brightness is higher. At the same time, the NTSC color gamut of the existing technology LCD light valve 8' is about 50% (CF efficiency as high as 25%), while the color gamut of the output image of this embodiment is at least > 75%. There is an essential gap in the user experience. It has significantly improved the power consumption, heat dissipation and noise levels of the projector. In addition, the black insertion also makes a significant contribution to the black level and contrast of the projector.

[0110] Furthermore, in the existing pure field-sequential technology, when inserting black between each sub-frame, the influence time on the driving chip and the liquid crystal of the LCD light valve 8 is required to be at least 30-40% higher than that of this embodiment. For a driver up to 10 9 Hertz (GHz), a 30% higher frequency means essential differences in power consumption, chip architecture, manufacturing process, memory capacity, etc. And the liquid crystal response time needs to reach about 2-3 ms, which is too difficult to implement specifically. In this embodiment, even if the liquid crystal response time is 5-6 ms, it can still work normally. Correspondingly, when the liquid crystal response time is reduced from 5 ms to 3 ms, there is almost no stable mass production technology for LCD light valves at present. At the same time, due to the function of inserting black, the black-and-white decay time and gray-scale response time of the field-sequential alternating sub-pixels on the liquid crystal no longer have a great impact on the image; while the sub-pixels with color filters (such as the first sub-pixel 81), its mechanism is the same as the existing full-color technology and belongs to a mature technology.

[0111] Of course, compared with the full-color display technology such as Figure 10 , inserting black itself will significantly increase the bandwidth requirement of the driving chip. Then, between the red sub-frame, green sub-frame, and blue sub-frame, and between the full-color frames, if black is not inserted, is it better to control the lighting time interval of each color light source? The answer is no. Although the lighting intervals between the red light source 101, green light source 102, and blue light source 103 are made wider, that is, the lighting time is shorter. Theoretically, when the LCD light valve 8 does not display the sub-frame images of each color normally (maintains), the LED light source does not light up, and the audience will not see abnormal phenomena such as image trailing and ghosting. But in fact, it is not the case. Since its mechanism has no necessary connection with the present invention, it will not be elaborated here.

[0112] Refer to Figure 5 As shown, for the green color filter photoresist (which can also be called color resist, and there is no strict distinction between "photoresist" and "color resist" in the industry) curve of the first sub-pixel 81 in this embodiment, light with a wavelength > 485 nm and < 585 nm is transmitted, light with a wavelength < 465 nm and > 605 nm is blocked, light in the wavelength range of 465 nm to 485 nm is in a continuous transition state from blocking to transmission, and light in the wavelength range of 585 nm to 605 nm is in a continuous transition state from blocking to transmission. Figure 5 In it, TS represents the transmission efficiency, and λ represents the wavelength.

[0113] Refer to Figure 6As shown, it is a schematic diagram of the spectral splitting of the LED light source. After combining light and filtering the light through a combined light and color filter device (the industry's terms for "combining light" and "combining colors" are not clearly distinguished. Although the strict definitions are different, the processes that produce effects are similar), the area of the local region enclosed by the two dashed lines and the abscissa in the figure must be ≤ 5% of the total area enclosed by the three-primary-color spectra (solid lines) and the abscissa in the figure. This is extremely helpful for improving indicators such as the color gamut, saturation, and contrast of the image, and at the same time, the loss of light energy is not significant. This is an empirical value.

[0114] In this embodiment, the combined light and color filter device includes a BG dichroic plate 31 and a CR dichroic plate 32. The light-emitting surfaces of the green light source 102 and the blue light source 103 are preferably arranged orthogonally, and the BG dichroic plate 31 is preferably at a 45° angle between the light-emitting surfaces (or corresponding optical axes) of the green light source 102 and the blue light source 103 to combine the light of the green light source 102 and the blue light source 103 (see Figure 1 shown). The BG dichroic plate 31 transmits blue light and reflects green light. Preferably but not limited to, light with a wavelength < 465nm is transmitted, light with a wavelength > 485nm is reflected, and light in the wavelength range of 465nm to 485nm correspondingly starts from 465nm, the transmittance gradually decreases until it is blocked at 485nm, and the change in transmittance is in a continuous transition state (if well-made, it is close to a linear transition state) rather than a step state.

[0115] In this embodiment, the light-emitting surfaces of the red light source 101 and the green light source 102 are preferably arranged in parallel or coplanarly, the CR dichroic plate 32 and the BG dichroic plate 31 are preferably arranged in parallel, and the CR dichroic plate 32 is between the light-emitting surfaces of the green light source 102 and the red light source 101 to combine the light from the BG dichroic plate 31 and the red light source 101. The CR dichroic plate 32 transmits cyan light and reflects red light. Preferably but not limited to, light with a wavelength < 585nm is transmitted, light with a wavelength > 605nm is reflected, and light in the wavelength range of 585nm to 605nm correspondingly starts from 585nm, the transmittance gradually decreases until it is blocked at 605nm, and the change in transmittance is in a continuous transition state. For the above details, see Figure 7 、 Figure 8 shown. In the figure, λ is the wavelength, TS is the transmittance, Ef is the efficiency, and RE is the reflectance. Considering the difficulty of coating, both the CR dichroic plate 32 and the BG dichroic plate 31 are selected to be arranged at a 45° angle with the optical axis. If arranged at other angles (assuming the installation space permits or the size of the whole machine requires), the balance between transmittance and reflectance needs to be sacrificed as appropriate.

[0116] It should be noted that, as described above, the dichroic plate is usually standard on DLP projectors with LED light sources, but it has never been introduced in single LCD projectors. At the same time, for DLP and single LCD projectors, the light splitting (or combining) characteristics of the dichroic plate are different. When the present invention is applied to the green light source 102, especially when the light source is excited by phosphor, active light filtering is required to meet the design requirements. For DLP projectors, the main purpose of the light combining device is to combine the light rays of the light source as efficiently as possible, because DLP projectors operate in an ideal pure field-sequential mode, and its white balance adjustment is much easier.

[0117] In this embodiment, inserting a black field into the second pixel 82 is a necessary measure to improve abnormal conditions such as image trailing, ghosting, and screen distortion. Before each sub-frame is displayed, the previous sub-frame displayed by the LCD light valve 8 is erased completely, which is similar to using the De-mura technology on the LCD light valve. Of course, this example is not appropriate. That is to say, before a scientific and efficient algorithm for accurately obtaining the "holding value" is found to avoid the incorrect superposition of the dynamic gray levels of the sub-frame images in the field sequence, erasing the screen and redisplaying it is the most effective means to achieve correct display.

[0118] To a certain extent, by adjusting the time or duty cycle of different first time periods t1 - t0, second time periods t2 - t1, third time periods t3 - t2, and fourth time periods t4 - t3, a very large number of color gamut, white balance, and output brightness options can be presented.

[0119] Embodiment Two:

[0120] Obviously, the engineering implementation of the pure field-sequential display technology with RGB sequence switching is extremely difficult. Therefore, in recent years, people have invented display technologies such as dual field-sequential and multi field-sequential. Refer to technologies such as Chinese Patent Publication Nos. CN104112436A and CN104134431A. Unfortunately, people still cannot make these products practical, especially for single LCD projectors.

[0121] Refer to Figures 1-3 、 Figure 9 As shown in and Embodiment One, the difference between this embodiment and Embodiment One is that: any pixel 801 of the LCD light valve 8 includes two black-and-white sub-pixels, namely the first sub-pixel 81 and the second sub-pixel 82; correspondingly, each full-color image input to the LCD light valve 8 is decomposed into sub-frame images of three primary colors: a red sub-frame, a green sub-frame, and a blue sub-frame.

[0122] The first sub-pixel 81 displays one of the sub-frame images of the three primary colors. In this embodiment, preferably but not limited to, the first sub-pixel 81 displays the green sub-frame image.

[0123] Correspondingly, the second sub-pixel 82 alternately displays the other two of the sub-frame images of the three primary colors in a field-sequential manner. In this embodiment, preferably but not limited to, the second sub-pixel 82 alternately displays the red sub-frame and the blue sub-frame images in a field-sequential manner.

[0124] Correspondingly, one light source in the LED light source corresponding to the color displayed by the first sub-pixel 81 is selectively lit with a duty cycle.

[0125] Correspondingly, when the second sub-pixel 82 displays one of the other two sub-frame images in a field-sequential manner, one light source of the corresponding color in the LED light source is selectively lit with a duty cycle; when the second sub-pixel 82 displays the other of the other two sub-frame images in a field-sequential manner, one light source of the corresponding color in the LED light source is selectively lit with a duty cycle. In this embodiment, when the second sub-pixel 82 displays the red sub-frame image in a field-sequential manner, the red light source 101 is selectively lit with a duty cycle; when the second sub-pixel 82 displays the blue sub-frame image in a field-sequential manner, the blue light source 103 is selectively lit with a duty cycle.

[0126] Further, assuming that the time taken to display each frame of the three-primary-color full-color image is T, and T is divided into a first time period t1 - t0, a second time period t2 - t1, a third time period t3 - t2, and a fourth time period t4 - t3, then T=(t1 - t0)+(t2 - t1)+(t3 - t2)+(t4 - t3)=t4 - t0. Correspondingly, the first sub-pixel (81) displays one of the three sub-frame images in the first time period t1 - t0 and the third time period t3 - t2, and inserts a black field in the second time period t2 - t1 and the fourth time period t4 - t3; Correspondingly, the second sub-pixel 82 alternately displays the other two sub-frame images in a field-sequential manner within the time T, specifically: a black field is inserted for the second sub-pixel 82 in the first time period t1 - t0, the second sub-pixel 82 displays one of the other two sub-frame images in the second time period t2 - t1, a black field is inserted for the second sub-pixel 82 in the third time period t3 - t2, and the second sub-pixel 82 displays the other of the other two sub-frame images in the fourth time period t4 - t3. Refer to Figure 9 As shown, in this embodiment, the first sub-pixel 81 displays the green sub-frame image in the first time period t1 - t0 and the third time period t3 - t2 (refer to Figure 9For the GC pulse curve, black fields are inserted during the second time period t2 - t1 and the fourth time period t4 - t3 (see the GBAC pulse curve); correspondingly, for the second sub-pixel 82, a black field is inserted during the first time period t1 - t0 (see the BAC pulse curve), the second sub-pixel 82 displays a red sub-frame image during the second time period t2 - t1 (see the RC pulse curve), a black field is inserted for the second sub-pixel 82 during the third time period t3 - t2 (see the BAC pulse curve), and the second sub-pixel 82 displays a blue sub-frame image during the fourth time period t4 - t3 (see the BC pulse curve).

[0127] Correspondingly, the green light source 102 corresponding to the color of the green sub-frame image displayed by the first sub-pixel 81 in the LED light source is selected to be correspondingly lit during the first time period t1 - t0 and the third time period t3 - t2 (see the GL pulse curve); in this embodiment, the green light source 102 is correspondingly lit within the time of <t1 - t0 and <t3 - t2 and is not lit during the remaining time of T.

[0128] In this embodiment, when the second sub-pixel 82 displays a red sub-frame image during the second time period t2 - t1, the red light source 101 is synchronously lit within the second time period t2 - t1, and the lighting time < the value of t2 - t1. When the second sub-pixel 82 displays a blue sub-frame image during the fourth time period t4 - t3, the blue light source 103 is synchronously lit within the fourth time period t4 - t3, but the lighting time < the value of 4 - t3.

[0129] Obviously, in this embodiment, due to the different LCD light valves, the lighting times of the LED light sources are also different, and the requirements for the driving chips of the LCD light valves are also different. On the one hand, the difficulty of driving the first sub-pixel 81 is increased, increasing the cost; on the other hand, if the input two same-color sub-frame images of the first sub-pixel 81 are processed by means of a memory in the front-end circuit, the clarity of the projector can be fully improved (showing more information); since the LCD light valve 8 does not have a CF, the manufacturing cost can be reduced to a certain extent.

[0130] Embodiment Three

[0131] A projection method of a field-sequential single-LCD projector provided in this embodiment includes the following steps:

[0132] The red light source 101, the green light source 102, and the blue light source 103 respectively emit light. The red light collection and collimation module collects and collimates the light emitted by the red light source 101, the green light collection and collimation module collects and collimates the light emitted by the green light source 102, and the blue light collection and collimation module collects and collimates the light emitted by the blue light source 103.

[0133] The light combining and color filtering device combines and filters the light emitted by the red light collection and collimation module, the green light collection and collimation module, and the blue light collection and collimation module. After being reflected by the intermediate mirror 4 and focused by the focusing device in sequence, the image of the LED light source is focused on or near the incident end face of the light homogenizing device 6, thereby forming a real image of the secondary light source. After the light homogenizing device 6 homogenizes the light of the real image of the secondary light source, the LCD light valve 8 is uniformly illuminated by the exit lens group 7, and then projected out through the field lens 9, the imaging mirror 10, and the projection lens 11 in sequence.

[0134] In this embodiment, the first sub-pixel 81 of the LCD light valve 8 displays one of the sub-frame images of the three primary colors. Correspondingly, one light source in the LED light source corresponding to the sub-frame color displayed by the first sub-pixel 81 is selectively lit with a duty cycle. The second sub-pixel 82 alternately displays the other two sub-frame images in a field-sequential manner. Correspondingly, two light sources in the LED light source corresponding to the colors of the other two sub-frame images are synchronously and alternately lit with a selective duty cycle corresponding to the two sub-frame images alternately displayed by the second sub-pixel 82.

[0135] Further, the area ratio δ of the first sub-pixel 81 and the second sub-pixel 82 in any one pixel is:

[0136] δ = S 81 / S 82 ;

[0137] δ = f(Φ 81 , Φ 821 , Φ 822 );

[0138] Where: S 81 is the area of the first sub-pixel 81; S 82 is the area of the second sub-pixel 82; Φ 81 is the luminous flux provided by the first sub-pixel 81; Φ 821 is the luminous flux provided by the second sub-pixel 82 when field-sequentially displaying one sub-frame image of the other two primary colors; Φ 822 is the luminous flux provided by the second sub-pixel 82 when field-sequentially displaying the other sub-frame image of the other two primary colors.

[0139] Further, the relationship between Φ 81 , Φ 821 , Φ 822 , the time consumption T of each frame of full-color image, and the optoelectronic characteristics of the LED light source is as follows:

[0140] Φ 81 = f{[β(Φ R , ΦG , Φ B ), Δt a , Δt c};

[0141] Φ 821 = f{[β(Φ R , Φ G , Φ B )], Δt b};

[0142] Φ 822 = f{[β(Φ R , Φ G , Φ B )], Δt d};

[0143] Where: β represents the mathematical meaning of "one of them" or "the corresponding one among them", that is, only the optoelectronic characteristics of one light source corresponding to the display color of the first sub-pixel 81 are counted, and the same applies hereinafter; Φ R , Φ G , Φ B ; Φ is the optoelectronic characteristic of the red light source 101; Φ R is the optoelectronic characteristic of the green light source 102; Φ G is the optoelectronic characteristic of the blue light source 103; Δt B is related to the first time period t1 - t0, that is, the proportion or duty cycle within the first time period t1 - t0; Δt a is related to the second time period t2 - t1, that is, the proportion or duty cycle within the second time period t2 - t1; Δt b is related to the third time period t3 - t2, that is, the proportion or duty cycle within the third time period t3 - t2; Δt c is related to the fourth time period t4 - t3, that is, the proportion or duty cycle within the fourth time period t4 - t3. d 81

[0144] By establishing a mathematical model through this method, the reasonable values of S 81 and S 82 can be accurately evaluated, thereby laying a scientific and feasible foundation for specific implementation.

[0145] The basic principles, main features and advantages of the present invention have been shown and described above. Those skilled in the art should understand that the present invention is not limited by the above embodiments. What is described in the above embodiments and the specification only illustrates the principles of the present invention. Without departing from the spirit and scope of the present invention, various changes and improvements will occur to the present invention, and these changes and improvements all fall within the scope of the present invention claimed. The scope of protection claimed by the present invention is defined by the appended claims and their equivalents.

Claims

1. A field sequential single LCD projector, characterized in that it includes an LED light source, a light collection and collimation device, a light combining and color filtering device, an intermediate mirror (4), a focusing device, a light homogenization device (6), an exit lens group (7), an LCD light valve (8), a field lens (9), an imaging mirror (10) and a projection lens (11) arranged in sequence along the light traveling direction; the LED light source includes a red light source (101), a green light source (102) and a blue light source (103); the light collection and collimation device includes a red light collection and collimation module for collecting and collimating the light emitted by the red light source (101), a green light collection and collimation module for collecting and collimating the light emitted by the green light source (102), and a blue light collection and collimation module for collecting and collimating the light emitted by the blue light source (103); each of the red light collection and collimation module, the green light collection and collimation module and the blue light collection and collimation module includes at least one lens; the light combining and color filtering device combines and filters the light emitted by the red light collection and collimation module, the green light collection and collimation module and the blue light collection and collimation module; the focusing device focuses the image of the LED light source on the incident end face of the light homogenization device (6), thereby forming a real image of a secondary light source; the focusing device includes at least one lens; after the light homogenization device (6) homogenizes the light of the real image of the secondary light source, the exit lens group (7) uniformly illuminates the LCD light valve (8); the LCD light valve (8) is a half-field sequential display light valve with a single primary color filter film, and any pixel (801) of the LCD light valve (8) includes two sub-pixels, namely a first sub-pixel (81) and a second sub-pixel (82); correspondingly, each full-color image input to the LCD light valve (8) per frame is decomposed into sub-frame images of three primary colors, namely a red sub-frame, a green sub-frame and a blue sub-frame; let the time taken to display each frame of the full-color image be T: the first sub-pixel (81) has a single primary color filter film, and within the T, the first sub-pixel (81) selectively displays one sub-frame image among the sub-frame images of the three primary colors that is the same as the color of the filter film; the second sub-pixel (82) has no filter film, and correspondingly, within the T, the second sub-pixel (82) alternately displays the other two sub-frame images among the sub-frame images of the three primary colors in a field sequential manner; correspondingly, one light source in the LED light source corresponding to the color of the filter film of the first sub-pixel (81) is selectively lit with a duty cycle; correspondingly, when the second sub-pixel (82) displays one of the other two sub-frame images in a field sequential manner, one light source in the LED light source corresponding to one color of a sub-frame image is selectively lit with a duty cycle; correspondingly, when the second sub-pixel (82) displays the other of the other two sub-frame images in a field sequential manner, one light source in the LED light source corresponding to the other sub-frame image is selectively lit with a duty cycle.

2. A field-sequential single LCD projector according to claim 1, wherein T is divided into a first time period t1 - t0, a second time period t2 - t1, a third time period t3 - t2, and a fourth time period t4 - t3, then T=(t1 - t0)+(t2 - t1)+(t3 - t2)+(t4 - t3)=t4 - t0; correspondingly, the first sub-pixel (81) displays a sub-frame image in time T; the second sub-pixel (82) alternately displays another two sub-frame images in a field-sequential manner within time T, specifically: during the first time period t1 - t0, a black field is inserted for the second sub-pixel (82), during the second time period t2 - t1, the second sub-pixel (82) displays one of the other two sub-frame images, during the third time period t3 - t2, a black field is inserted for the second sub-pixel (82), and during the fourth time period t4 - t3, the second sub-pixel (82) displays the other of the other two sub-frame images; Correspondingly, a light source corresponding to the color of the color filter film of the first sub-pixel (81) in the LED light source is selected to be correspondingly lit during the first time period t1 - t0 and the third time period t3 - t2; Correspondingly, when the second sub-pixel (82) displays one of the other two sub-frame images during the second time period t2 - t1, a light source corresponding to the color of one sub-frame image in the LED light source is selected to be lit within the second time period t2 - t1 for a time ≤t2 - t1; Correspondingly, when the second sub-pixel (82) displays the other of the other two sub-frame images during the fourth time period t4 - t3, a light source corresponding to the color of the other sub-frame image in the LED light source is selected to be lit within the fourth time period t4 - t3 for a time ≤t4 - t3.

3. A field-sequential single LCD projector according to claim 1, wherein The light combining color filter device includes a BG dichroic plate (31) and a CR dichroic plate (32); The light emitting surfaces of the green light source (102) and the blue light source (103) are neither parallel nor coplanar; the BG dichroic plate (31) is located between the light emitting surfaces of the green light source (102) and the blue light source (103) and combines the green light source (102) and the blue light source (103); The light emitting surfaces of the red light source (101) and the green light source (102) are parallel, coplanar, non-parallel, or non-coplanar; the CR dichroic plate (32) combines the light rays from the BG dichroic plate (31) and the red light source (101).

4. A field-sequential single LCD projector according to claim 1, wherein The light rays emitted from the light combining color filter device have: the spectral distributions of the red, green, and blue light rays do not overlap with each other, and the light combining color filter device outputs pure three-primary-color light rays; the overlapping spectra are filtered and blocked by the light combining color filter device.

5. A field-sequential single LCD projector according to claim 1, wherein The light emitted from the light combining and color filtering device has the following characteristics: the wavelength range where the spectral distributions of red, green, and blue light overlap is ≤50 nm, and the area of the overlapping region is ≤5% of the area enclosed by the spectrum of the light emitted from the light combining and color filtering device; for the overlapping spectral wavelengths >50 nm with an overlapping area >5% of the area enclosed by the spectrum of the light emitted from the light combining and color filtering device, it is filtered and blocked by the light combining and color filtering device.

6. A field-sequential single LCD projector according to claim 1, wherein the red light collection and collimation module includes an R collection lens (211) and an R collimation lens (212) arranged in sequence along the light traveling direction; the green light collection and collimation module includes a G collection lens (221) and a G collimation lens (222) arranged in sequence along the light traveling direction; the blue light collection and collimation module includes a B collection lens (231) and a B collimation lens (232) arranged in sequence along the light traveling direction.

7. A field-sequential single LCD projector according to claim 1, wherein the light homogenizing device includes a square pyramid condenser.

8. A field-sequential single LCD projector according to claim 1, wherein the exit lens group (7) includes at least one lens, the lens is a plano-convex free-form surface lens, the plane of the free-form surface lens is the incident surface, and the exit surface of the free-form surface lens is a free-form surface.

9. A field-sequential single LCD projector, characterized in that it includes an LED light source, a collection and collimation device, a light combining and color filtering device, an intermediate mirror (4), a focusing device, a light homogenizing device (6), an exit lens group (7), an LCD light valve (8), a field lens (9), an imaging mirror (10), and a projection lens (11) arranged in sequence along the light traveling direction; the LED light source includes a red light source (101), a green light source (102), and a blue light source (103); the collection and collimation device includes a red light collection and collimation module for collecting and collimating the light emitted from the red light source (101), a green light collection and collimation module for collecting and collimating the light emitted from the green light source (102), and a blue light collection and collimation module for collecting and collimating the light emitted from the blue light source (103); the red light collection and collimation module, the green light collection and collimation module, and the blue light collection and collimation module each include at least one lens; the light combining and color filtering device combines and filters the light emitted from the red light collection and collimation module, the green light collection and collimation module, and the blue light collection and collimation module; the focusing device focuses the image of the LED light source at the incident end face of the light homogenizing device (6) to form a real image of the secondary light source; the focusing device includes at least one lens; after the light homogenizing device (6) homogenizes the light of the real image of the secondary light source, the exit lens group (7) uniformly illuminates the LCD light valve (8). The LCD light valve (8) is a black-and-white type half-sequential display light valve. Any pixel (801) of the LCD light valve (8) includes two black-and-white sub-pixels, namely a first sub-pixel (81) and a second sub-pixel (82); correspondingly, each full-color image input to the LCD light valve (8) per frame is decomposed into sub-frame images of three primary colors, namely a red sub-frame, a green sub-frame, and a blue sub-frame; let the time taken to display each frame of the full-color image be T: The first sub-pixel (81) selectively displays one of the sub-frame images of the three primary colors within the T; Correspondingly, the second sub-pixel (82) alternately displays the other two of the sub-frame images of the three primary colors in a field-sequential manner within the T; Correspondingly, one light source in the LED light source corresponding to the color of one sub-frame image displayed by the first sub-pixel (81) is selectively lit with a duty cycle; Correspondingly, when the second sub-pixel (82) displays one of the other two sub-frame images in a field-sequential manner, one light source in the LED light source corresponding to the color of one sub-frame image is selectively lit with a duty cycle; Correspondingly, when the second sub-pixel (82) displays the other of the other two sub-frame images in a field-sequential manner, one light source in the LED light source corresponding to the color of the other sub-frame image is selectively lit with a duty cycle.

10. The field-sequential single-LCD projector according to claim 9, wherein Let T be divided into a first time period t1 - t0, a second time period t2 - t1, a third time period t3 - t2, and a fourth time period t4 - t3, then T = (t1 - t0) + (t2 - t1) + (t3 - t2) + (t4 - t3) = t4 - t0; Correspondingly, the first sub-pixel (81) displays one of the sub-frame images of the three primary colors in the first time period t1 - t0 and the third time period t3 - t2, and inserts a black field in the second time period t2 - t1 and the fourth time period t4 - t3; Correspondingly, the second sub-pixel (82) alternately displays the other two sub-frame images of the three primary colors in a field-sequential manner within the T, specifically: a black field is inserted for the second sub-pixel (82) in the first time period t1 - t0, the second sub-pixel (82) displays one of the other two sub-frame images of the three primary colors in the second time period t2 - t1, a black field is inserted for the second sub-pixel (82) in the third time period t3 - t2, and the second sub-pixel (82) displays the other of the other two sub-frame images of the three primary colors in the fourth time period t4 - t3; Correspondingly, one light source in the LED light source corresponding to the color of one sub-frame image of the three primary colors displayed by the first sub-pixel (81) is selected to be lit corresponding to the time ≤t1 - t0 and ≤t3 - t2 within the first time period t1 - t0 and the third time period t3 - t2; Correspondingly, when the second sub-pixel (82) displays one of the sub-frame images of the other two primary colors during the second time period t2 - t1, one light source among the LED light sources corresponding to the color of one sub-frame image is selected to be lit within the second time period t2 - t1 for a time ≤ t2 - t1. Correspondingly, when the second sub-pixel (82) displays the other of the sub-frame images of the other two primary colors during the fourth time period t4 - t3, one light source among the LED light sources corresponding to the color of the other sub-frame image is selected to be lit within the fourth time period t4 - t3 for a time ≤ t4 - t3.

11. A projection method of a field-sequential single LCD projector as claimed in claim 2, characterized in that: It includes the following steps: The red light source (101), green light source (102), and blue light source (103) respectively emit light. The red light collection and collimation module collects and collimates the light emitted by the red light source (101), the green light collection and collimation module collects and collimates the light emitted by the green light source (102), and the blue light collection and collimation module collects and collimates the light emitted by the blue light source (103). The light combining and color filtering device combines and filters the light emitted by the red light collection and collimation module, the green light collection and collimation module, and the blue light collection and collimation module. After being reflected by the intermediate mirror (4) and focused by the focusing device in sequence, the image of the LED light source is focused on the incident end face of the light homogenizing device (6), thereby forming a real image of the secondary light source. After the light homogenizing device (6) homogenizes the light of the real image of the secondary light source, the LCD light valve (8) is uniformly illuminated by the outgoing lens group (7). After the light passes through the LCD light valve (8), it is projected out through the field lens (9), imaging mirror (10), and projection lens (11) in sequence. The first sub-pixel (81) of the LCD light valve (8) displays one of the sub-frame images of the three primary colors. Correspondingly, one light source among the LED light sources corresponding to the color of one sub-frame image displayed by the first sub-pixel (81) is selectively lit with a duty cycle. The second sub-pixel (82) alternately displays the sub-frame images of the other two primary colors in a field-sequential manner. Correspondingly, two light sources among the LED light sources corresponding to the colors of the sub-frame images of the other two primary colors are synchronously and alternately selectively lit with a duty cycle corresponding to the two sub-frame images alternately displayed by the second sub-pixel (82).

12. The projection method according to claim 11, wherein The ratio δ of the areas occupied by the first sub-pixel (81) and the second sub-pixel (82) in any one pixel (801) is: δ = S 81 / S 82 ; δ = f(Φ 81 , Φ 821 , Φ 822 ); Wherein: S 81 is the area of the first sub-pixel (81); S 82 is the area of the second sub-pixel (82); Φ81 is the luminous flux provided by the first sub-pixel (81); Φ 821 is the luminous flux provided by the second sub-pixel (82) when sequentially displaying a sub-frame image of the other two primary colors in a field; Φ 822 is the luminous flux provided by the second sub-pixel (82) when sequentially displaying another sub-frame image of the other two primary colors in a field.

13. According to the projection method as claimed in claim 12, characterized in that: The described Φ 81 , Φ 821 , Φ 822 The relationship between the time T required for each full-color image frame and the optoelectronic characteristics of the LED light source is as follows: Φ 81 = f{[β(Φ R , Φ G , Φ B )], Δt a , Δt c}; Φ 821 = f{[β(Φ R , Φ G , Φ B )], Δt b}; Φ 822 = f{[β(Φ R , Φ G , Φ B )], Δt d}; Wherein: β represents "one of the corresponding ones", that is, only Φ is counted R , Φ G , Φ B and the optoelectronic characteristics of a light source corresponding to the display color of the first sub-pixel 81; Φ R is the optoelectronic characteristic of the red light source (101); Φ G is the optoelectronic characteristic of the green light source (102); Φ B is the optoelectronic characteristic of the blue light source (103); Δt a is related to the first time period t1 - t0, that is, the proportion or duty cycle occupied within the first time period t1 - t0; Δt b is related to the second time period t2 - t1, that is, the proportion or duty cycle occupied within the second time period t2 - t1; Δt c is related to the third time period t3 - t2, that is, the proportion or duty cycle occupied within the third time period t3 - t2; Δt d is related to the fourth time period t4 - t3, that is, the proportion or duty cycle occupied within the fourth time period t4 - t3.

Images